Horizontal earth boring method



Feb. 20, 1968 J. B. BRACK ETAL 3,369,617

HORIZONTAL EARTH BORING METHOD Filed June '7, 1965 50 2 Geo/ye fl.Penn/092% 55 0 LT Char/e: J zfafi/rsan /0 m Cuff/J E. Pennmg/on 2:2 15:5 INVENTORS v 6/ lo 55 By o #agdm d? J /0 14 TTORNE YS 3,369,617HORIZONTAL EARTH BORING METHOD Joe B. Brack, George R. Pennington,Charles J. Johnson, and Curtis E. Pennington, Baytown, Tex., assignors,by mesne assignments, to Gilbert M. Turner, Houston, Tex.

Filed June 7, 1965, Ser. No. 461,694 4 Claims. (Cl. 17562) ABSTRACT OFTHE DISCLOSURE A method of forming an enlarged horizontal bore with areamer having forward and rearward cutting teeth, a central fluid supplypassage and communicating ports adjacent the cutting teeth comprisingrotating and advancing the reamer to form an enlarged horizontal borewhile discharging water from the reamer to mix with the cuttings,reversing the direction of advance of the reamer while continuing therotation to reduce the size of the cuttings, again reversing thedirection of advance of the reamer to move the reamer forwardly of thecuttings and introducing compressed gas into the bore hole through theports in the reamer to move the cuttings outwardly of the bore.

This invention relates to new and useful improvements in earth boringmethods and apparatus, and particularly methods and apparatus whereinsubstantially horizontal holes are drilled beneath a road, railroad, orsimilar area.

Various work has been done in the past in the field of earth boringwherein horizontal holes are drilled beneath a road, railroad, or thelike, as illustrated by US. Patent Nos. 1,932,068, 2,234,451, 2,693,345,2,702,180, and 3,011,567. In US. Patent No. 2,702,180, a method ofdrilling horizontal bore holes is disclosed wherein compressed air isused to eject the cuttings from the boring or drilling operation, butsuch method involves a series of steps which render such method complex,Thus, in the method of Patent No. 2,702,180, a first mass of cuttings isformed, such first mass is compacted by withdrawing the reamer or drill,water is injected into the space inwardly of the withdrawn reamer, thereamer is then advanced for drilling a second mass of cuttings, thereamer is again withdrawn to compact the second mass of cuttings, andthen the compressed air is used to force the two masses outwardly.

An object of the present invention is to provide a new and improvedearth boring method and apparatus which uses compressed air or gas forejecting cuttings but which obviates the complex methods employed in theprior art.

An important object of this invention is to provide a new and improvedearth boring method and apparatus which is particularly suitable fordrilling substantially horizontal bore holes and which is elfective fordischarging the cuttings by means'of compressed gas and withoutcompacting the cuttings with the reamer or drill or introducing liquidinto a space between two compacted masses before applying the compressedair or other gas.

A particular object of this invention is to provide a new and improvedearth boring method and apparatus wherein reverse reaming is effectedfor a triple cut accompanied by a discharge of water into the cuttingsor particles to fluidize the cuttings or particles so that they may beejected from the bore hole with compressed air.

Another object of this invention is to provide a new and improved reameror drill which has an open face and rows of cutting teeth extendingsubstantially radially on both the forward and rear for therebyproviding cutting action when moving in inwardly and outwardly in thedrilling of a bore hole.

The preferred embodiment of this invention will be de- States Patent3,369,617 Patented Feb. 20, 1968 scribed hereinafter, together withother features thereof, and additional objects will become evident fromsuch description.

The invention will be more readily understood from a reading of thefollowing specification and by reference to the accompanying drawingsforming a part thereof, wherein an example of the invention is shown,and wherein:

FIG. 1 is a view, partly in elevation and partly in section,illustrating the first phase of the method of this invention;

FIG. 2 is a view similar to FIG. 1, but illustrating a further phase ofthe method of this invention;

FIG. 3 is also a view similar to FIGS. 1 and 2, but illustrating a stillfurther phase of the method of this invention;

FIG. 4 is an elevation of the reamer apparatus of this invention whichis used in performing the method illustrated schematically in FIGS. 1-3;and

FIG. 5 is a view taken on line 55 of FIG. 4 to further illustrate theconstruction of the reamer of this invention.

In the drawings, the letter R designates generally the reamer or drillof this invention, which is used in carrying out the method of thisinvention. Briefly, the reamer R is used in drilling or cutting a borehole B which is normally substantially horizontal. In the usual case,the bore hole B is cut or drilled in the earth beneath a road X, arailroad or other similar area. After the bore hole B is completelydrilled and the cuttings therefrom are removed, such bore hole B mayserve as a culvert for con ducting water or other materials beneath theroad X or other similar area. As will be explained more in detailhereinafter, the method of this invention provides for a multiplecutting of the cuttings from the bore hole so as to reducethe particlesize of such cuttings while also fiuidizing them with water, therebyfacilitating the removal of the cuttings from the bore hole B withcompressed air or other gas. The reamer R which is used in the method ofthis invention is of the open type and it has forward cutter teeth 10and rear cutter teeth 12, as will be described more in detailhereinafter.

Considering the invention more in detail, the method is initiated bydrilling a pilot hole 15, preferably for the full length of the sectionin which the bore hole B is to be drilled. Such pilot hole 15 is drilledwith any conventional drill bit and is normally accomplished in a singledrilling operation from one side of the embarkment E to the other. Onetype of standard drilling apparatus which may be used for operating thepilot bit (not shown) for drilling the pilot hole 15 and for alsooperating the reamer R is illustrated in United States Patent No.1,932,068, and it in itself forms no part of this invention.

After the pilot hole 15 has been drilled, a leader pipe 16 is connectedto the reamer R at the forward end of such reamer R, and a section ofdrill stem or pipe 20 is connected to the reamer R at its rear portion.The drill stem 20 is rotated by any suitable drilling apparatus such asthat illustrated in the United States Patent No. 1,932,- 068 so as toimpart rotation to the drill stem 20 and the reamer R.

The leader pipe is normally about two to three feet in length, and it isinserted initially into the bore hole 15;

then rotation of the drill stern and reamer R are commenced to begin thedrilling of the bore hole B which is normally of a substantially largerdiameter than the pilot hole 15. During such drilling action, theforward cutting teeth 10 on the reamer R cut the bore hole B and leavecuttings 25' of earth in the bore hole B behind the reamer R. A liquidsuch as water is introduced through the hollow drill stem 20 and thereamer R, as will be more fully explained in connection with thedescription of the ream- 3 er R hereinafter so as to distribute thewater throughout the cuttings 25.

It has been found that with many types of soils the cuttings 25 may bedischarged from the hole B by the introduction of compressed air orother gas in place of the liquid after the reamer R has drilled for apredetermined distance or stroke, such as three to six feet. When thecompressed air or gas is used for such discharge'of the cuttings 25, theintroduction of liquid into the drill stem 20 is stopped; and, instead,the compressed air or gas is introduced through the drill stem 20 fordischarge at the reamer R when it is at the forward end of its stroke.

In those instances wherein the cuttings 25 are not ejected or movedoutwardly of the bore hole B by the compressed air or gas after only thesingle stroke of the reamer R, a complex scheme has heretofore been proposed by the prior art, as explained above, to accomplish the ejectionof the cuttings. However, with the present invention, the removal of thecuttings 25 is accomplished with a relatively simple but highlyeffective method.

Thus, if by reason of the consistency of the cuttings 25, or if for anyother reason, the cuttings 25 cannot be ejected by the compressed airorgas after the initial longitudinal movement of the reamer R throughoutits stroke in one direction to a point such as indicated in FIG. 1 ofthe drawings, then the method of this invention includes the subsequentsteps which are schematically illustrated in FIGS. 2 and 3 of thedrawings. .For example, the next step of the method preferably includesthe rotation of the drill stem 20 and the reamer R in the same directionas when initially drilling the bore hole 13 to the end as shown in FIG.1, but the direction of longitudinal movement of the reamer R isreversed as shown in FIG. 2. During the reverse longitudinal movement ofthe reamer R, the rear cutting teeth 12 cut the cuttings 25 into smallerparticles 25a which remain forwardly of the reamer R in the bore hole B,and thus compacting of the cuttings is avoided. The reverse cuttingaction with the rear cutting teeth 12 is preferably continued for all,or substantially all, of the distance through which the reamer Rinitially traveled when cutting the bore hole B with the forward cuttingteeth 10.

During the reverse longitudinal movement of the reamer R, water or otherliquid is discharged at the reamer R into the cuttings to furtherfluidize such cuttings as they are being reduced in size by the reversecutting action of the rear cutting teeth 12.

Thereafter, the reamer R and the drill stem 20 are moved forwardly againuntil they reach the end of the bore hole 26, which was the initialpoint at which the drilling with the reamer R was stopped in the firststroke. Such position of the reamer R is illustrated in FIG. 3. Duringthe forward movement of the reamer R for the second time, additionalcutting action is obtained with the forward cutting teeth so as to evenfurther reduce the particle size of the cuttings 25 as indicated by thenumeral 25b in FIG. 3. Water or other liquid is normally introducedwhile the cutting steps are taking place, including the final thirdcutting as the reamer R is moved forwardly for the second time. Thus,the complete cutting process involves a triple cutting of the cuttings25 to produce the smaller particle size cuttings illustrated at 2512 inFIG. 3. At the end of the stroke, with the reamer R in the positionshown in FIG. 3 in contact with the forward end 26 of the bore hole B,the cuttings have been reduced in size and thoroughly mixed with waterso as to be fluidized or formed into a slurry which is readilydischarged thereafter by compressed air or gas.

Therefore, as illustrated in FIG. 3, the introduction of the water orother liquid is replaced by the introduction of compressed air or gasthrough the drill stem and the reamer R for moving the cuttings boutwardly to eject same and substantially clean the bore hole B.

The method described above is then continued for another predetermineddistance or stroke, generally three 4 to six feet in length, and suchmethod is thus repeated until the full length of the bore hole has beenobtained underneath the road X or other area.

In FIGS. 4 and 5, the reamer R having the forward cutting teeth 10 andthe rear cutting teeth 12 are illustrated in detail. Thus, the reamer Rincludes an annular reamer support or ring which is formed of metal suchas steel. The space inwardly of the annular reamer support or ring 40 isopen and a drill stem connector element is disposed centrally of suchopening within the ring 40. The connector element 50 is supported in itscentral position by any suitable supports extending radially from theconnector 50 to the ring 40, and as illustrated in the drawings, suchsupports are tubular support members 55. The inner ends of the tubes arewelded to the connector element 50, while the outer ends of the tubularelements or tubes 55 are welded to the inner rim or surface of the ring40.2

Each of the support arms or tubes 55 has a cutter blade mounted thereonwith retaining bolts 61 or other suitable mounting means. Each of thecutter blades 60 has the forward cutting teeth 10 and the rear cuttingteeth 12- The connector element 50 is provided with internal threads5011 at one end for receiving a threaded male connection on the drillstem 20 (FIGS. 1-3). The connector element 50 has threads 50b formed atits forward end for making a threaded connection with the leader pipe 16(FIGS. 1-3).

For conducting the liquid during the drilling operations with the reamerR so as to distribute such liquid throughout the cuttings, the connectorelement 50 is hollow and its bore 500 is provided with an opening orhole Stldfor each of the tubes 55, and in alignment therewith so thatfluid from within the bore 50c flows into the interior of the tubes 55..Each ofthe tubes 55 has a plurality of outlets 55a for directing thefluid in the direction of the forward cutting teeth 10 and other outlets55b for directing the fluid in the direction of the rear teeth 12. Whenthe water is introduced through the drill stem 20, it is of coursedischarged through the openings 55a and 5512, whereas when thecompressed air or other gas is introduced through the drill. stem 20,the compressed air. or gas is discharged through the openings 55a and55b.

Since the cutting action required during the reverse longitudinalmovement of the reamer R in the direction illustrated in FIG. 2 isreduced as compared to the initial cutting action required when thereamer R is moved longitudinally forwardly for the initial cutitng. ofthe bore hole B, the angle of inclination of the cutter teeth.l2,.

with respect to horizontal, is normally about five degrees less than theangle of inclination of the cutter teeth 10 although they may be of thesame inclination in some instances. The entire reamer R is preferablyformed of. steel so that it is rugged in construction and may be used.

for many operations.

The foregoing disclosure and description of the invention isillustrative and explanatory thereof and various changes in the size,shape and materials, as well as in the details of the illustratedconstruction, may be made within the scope of the appended claimswithoutdeparting from the spirit of the invention.

What is claimed is:

1. A method of boring a substantially horizontal hole in the earth,comprising the steps of:

(a) rotating an open reamer having forward and rear cutting teeth andmoving such reamer in a longitudinal direction for cutting a bore holewith the forward cutting teeth,

(b) discharging water in proximity to the reamer for mixing with thecuttings as made by the reamer,

(c) reversing the direction of longitudinal movement of the reamer whilerotating same for cutting the cuttings into smaller particles with therear cutting teeth,

(d) thereafter again moving the reamer longitudinally forwardly of atleast some of the cutting particles, and

(e) discharging compressed gas rearwardly of the reamer for moving atleast some of the cutting particles outwardly in the bore hole.

2. A method of boring a substantially horizontal hole in the earth,comprising the steps of:

(a) rotating an open reamer having forward and rear cutting teeth andmoving such reamer in a longitudinal direction for cutting a bore holewith the forward cutting teeth,

(b) discharging Water in proximity to the reamer for mixing with thecuttings made by the reamer,

(c) reversing the direction of longitudinal movement of the reamer whilerotating same for cutting the cuttings into smaller particles with therear cutting teeth,

(d) discharging water into the smaller cutting particles to fluidize theparticles,

(e) thereafter again moving the reamer longitudinally forwardly throughthe cuttings until the reamer reaches approximately the inward extent ofthe bore hole, and

(f) introducing compressed gas inwardly of the fluidized cuttingparticles for moving them outwardly in the bore hole.

3. A method of boring a substantially horizontal hole in the earth,comprising the steps of:

(a) rotating an open reamer having forward and rear cutting teeth andmoving such reamer in a longitudinal direction for cutting a bore holewith the forward cutting teeth,

(b) discharging water in proximity to the reamer for mixing with thecuttings made by the reamer,

(c) reversing the direction of longitudinal movement of the reamer whilerotating same for cutting the cuttings into smaller particles with therear cutting teeth,

(d) discharging water into the smaller cutting particles to fiuidize theparticles,

(e) thereafter again reversing the direction of longitudinal movement ofthe reamer while rotating same for cutting the cuttings into stillsmaller particles with the forward cutter teeth,

(f) discharging water into the cuttings to further fluidize theparticles, and

(g) introducing compressed gas inwardly of the fluidized cuttingparticles for moving them outwardly in the bore hole.

4. A method of cutting a bore hole, comprising the steps of:

' (a) drilling a pilot hole,

(b) inserting a leader pipe on a reamer having forward and rear cuttingteeth,

(0) rotating the reamer and moving same longitudinally forwardly forcutting a bore hole with the forward cutting teeth,

((1) discharging water in proximity to the reamer for mixing with thecuttings as made by the reamer,

(e) reversing the direction of longitudinal movement of the reamer whilerotating same for cutting the cuttings into smaller particles with therear cutting teeth,

(f) thereafter again moving the reamer longitudinally forwardly of atleast some of the cutting particles, and

(g) discharging compressed gas rearwardly of the reamer for moving atleast some of the cutting particles outwardly in the bore hole.

References Cited UNITED STATES PATENTS 2,684,834 7/1954 Miller et al175-53 2,693,345 11/1954 Martin et al. 175-384 2,702,180 2/1955 Horner175-69 2,733,767 2/1956 Sappington 175-401 X 3,011,567 12/1961 Turner175-62 X 3,072,205 1/ 1963 Govin 175-62 X 40 ERNEST R. PURSER, PrimaryExaminer.

